1. Field of the Invention
The present invention relates to data storage devices, such as analog and digital memories used by and within computer systems, and more particularly to radiation hard, non-volatile data storage devices with non-destructive readout.
2. Description of the Prior Art
Conventional non-volatile memories (NVM's) fall into two broad classes,; archival and interactive. Archival NVM's use magnetic tape, floppy diskettes and hard disks. Interactive NVM's utilize digital integrated circuits (IC's) for electrical storage and read out of data. Such digital IC memories are widely used but have many limitations in terms of speed, density, cyclability and difficulty in configuring massively parallel systems and/or providing interfaces with optical signal handling systems.
Many alternate memory approaches have been proposed and are continuing to be developed. One promising approach has been the development of ferroelectric memory systems in which the remanent polarization of the ferroelectric material is used to store the data. Current approaches to such ferroelectric memory systems have included both bulk and thin film ferroelectric materials but have required destruction of the remanent polarization in order to electronically read or retrieve the data.
A substantial improvement in such systems has been proposed in which bulk ferroelectric materials are used in a ceramic form as a non-volatile memory storage element. In such devices, optical addressing of the data stored produces an electrical output signal without destruction of the remanent polarization.
What is needed, however, is a new approach to memory storage elements providing increased density, electro-optic compatibility, high speed operation, increased cyclability and improved radiation hardness. The new approach should provide non-destructive optical addressing of stored information and overcome the electronic cross talk and pinout limitations inherent in conventional large interconnection arrays.
In addition, computer system architecture design would benefit greatly from the availability of memory systems capable of analog as well as digital data storage ability. The ability to perform some computing functions in the memory, that is, alter the output resulting from a read out of the memory as a controllable function of the input and stored information, would substantially enhance computer architecture design flexibility and performance.